Amyloidomas of soft parts: diagnosis by fine-needle aspiration

A tumoral mass of amyloid (amyloidoma) arising in the soft tissues of the distal extremities is exceedingly unusual, and applying the fine-needle aspiration (FNA) biopsy technique to specifically diagnose this condition is even more infrequent. Herein, we report an example of two separate amyloidomas arising in the right calf of an otherwise asymptomatic elderly man who was referred to the sarcoma clinic because these masses clinically and radiographically simulated a malignant neoplasm. The fine-needle aspirate yielded amorphous, acellular, dense blue material on Romanowsky-stained smears and smudgy acellular cyanophilic material on Papanicolaou-stained smears. The aspirate procured cell-block contained hyalinized eosinophilic acellular material on H&E stain that was Congo-red positive and displayed yellow-green birefringence with polarization. Unlike prior assertions to the contrary, a diagnosis of amyloidoma is possible using FNA cytopathology even in patients without a known underlying amyloidogenic disorder.